Runaway millionaire Hui ''Leo'' Gao, who lived the high life for 2-1/2 years on Westpac's money, will spend less time than that in jail for his crimes.

He will be freed from prison on December 23, despite there being no clear answer to how much of the unrecovered $3.7 million he still controls.

Westpac bank, whose employee wrongly gave Gao's failing Rotorua service station business an overdraft of $10m instead of $100,000, said yesterday it would not comment on his release.

The bank recovered about $3m soon after it was discovered Gao had transferred $6.78m from his account.

The Parole Board says that, despite the ''sizeable nature'' of his fraud, Gao can be freed just four days after he first becomes eligible for parole. It was concerned only with his risk of reoffending, it said in a decision made public yesterday.

It believed strict parole conditions lasting until January 2017 could adequately manage that risk.

The board said Gao, 33, had explained to it in ''some detail'' what happened when he left New Zealand just days after discovering the bank's mistake in April 2009. The board said of the money: ''It would seem as if much of it was dissipated on living expenses and in the casinos.''

However, the Court of Appeal, when it dismissed Gao's appeal against his sentence of four years and seven months earlier this year, said it should be assumed that he still had control of the money.

The court said that, if Gao wanted to be treated as if he no longer had the money, it was incumbent on him to say what happened to it.

''To date he has not done so.

"The court is therefore entitled to proceed on the basis that Mr Gao has retained control of the funds, and will have access to them once he is released from prison.''

Gao's former partner, Kara Hurring, followed him to Hong Kong but returned voluntarily in February 2011, and was sentenced to home detention for her part in his crimes.

When contacted yesterday, Hurring - who now lives in Blenheim and works at an eyelash studio - was unwilling to discuss Gao's parole.

''What does that have to do with me? I don't want any comment or anything to do with this story, so please keep my name out of it, thank you.''

The Parole Board has said any contact between the two - who have a daughter - is subject to a probation officer's oversight, at least at first.